Ubiquitous video communication is commonly agreed to be an ultimate goal of modern communication services. Yet, even in view of rapid advances and deployment of computing technology and the relative ease and dearth of computing device interconnectivity opportunities, video communication is still not very common. In part, this is because of the lack of a video codec (encoder/decoder) that can produce and present high quality video across the substantially large range of network bandwidths that are utilized by many of the available communication devices (e.g., handheld PCs, personal digital assistants (PDAs), mobile phones, laptops, desktops, etc.).
For example, even though popular video compression technologies such as Moving Pictures Expert Group (MPEG) and H.263 compression techniques have been used for quite some time, these compression techniques still do not provide satisfactory and smooth video frame encoding and transmission at currently popular bandwidth ranges, for instance, at 33.6 Kbps or below. Rather, in low bandwidth conditions (e.g., below 33.6 Kbps), such conventional techniques typically result in images that look like an ill-fitted collection of a limited selection of color blocks, and wherein scene motion is abnormally discontinuous. Such undesirable ill-fitted collections of color blocks is determined to originate from the common discrete cosine transform (DCT) based coding architecture of the MPEG, MPEG2, MPEG4 and H.263 coding/decoding (“codec”) algorithms.
In particular, DCT-based coding algorithms group pixels into blocks, e.g. 8×8 or 16×16 pixel blocks. Such blocks are then transformed from a spatial domain into a set of DCT coefficients in the frequency domain. Each DCT coefficient is weighted according to a corresponding DCT basis waveform. These coefficients are then quantized, and nonzero quantized values are compressed using an entropy coder. As a result, low spatial frequency values that represent “basic colors” of the blocks are provided with a high priority. Thus, if DCT-based compression methods work in very low bandwidth condition, the basic colors of the blocks will be kept in preference; thereby, generating the blocky and undesirable color defects in the resulting image.
While the above compression methods would not present a problem in situations where broad bandwidths are available, this is not the case when the video broadcast or communication is to be performed using low bandwidth devices, such as handheld PCs, palm-size PCs or mobile phones. These devices typically operate at bandwidths around 9.6 to 28.8 Kbps, but can operate even below 9.6 Kbps. When a typical broadcast color video is viewed on a low bandwidth device, the result is generally unsatisfactory, as indicated above. These problems, among others, discourage wide application of video communication.
Accordingly, systems and methods to satisfactorily communicate video across a wide range of bandwidth conditions, including low bandwidth conditions that over time may increase with respect to their data throughput capabilities, or vice-versa, are greatly desired.